Air cargo pallets are commonly used to support and secure cargo during transportation via aircraft. In many applications, particularly military applications, passenger seats for transporting passengers may be mounted on the pallets. These types of seating pallets allow cargo aircraft, which have few or no permanent passenger seats, to be rapidly equipped with large numbers of passenger seats.
Existing air cargo pallets typically include top and bottom aluminum sheets attached to a core. Traditional air cargo pallets typically included a balsa core, while modern pallets have been developed that include a core of aluminum stringers running lengthwise between the top and bottom aluminum sheets. Lateral struts are typically positioned perpendicularly to the stringers to strengthen the pallet. Examples of air cargo pallets having a core of aluminum stringers and lateral struts are described in U.S. Pat. No. 4,690,360, incorporated herein by reference.
Air cargo pallets used for passenger seating typically include linear seat tracks attached to the top metal sheet of the pallets. Seats are connected to the linear tracks via fittings on the seats or via separate attachments. The seats and/or the seat attachments typically include one or more locking devices to temporarily lock the seat into place on the linear tracks, such that the seat may be shifted forward or backward along the tracks when the locking device is disengaged, and then locked into place by engaging the locking device.
While this seating system has worked relatively well, the linear tracks occasionally become loosened from the pallet over time, due to the heavy loads applied to the tracks, particularly when the aircraft encounters heavy turbulence or other rough flying or landing conditions. In these cases, the tracks often have to be replaced, which can be time-consuming and expensive. There is also the possibility that the tracks could break free from the pallet under extreme load conditions, such as during an emergency landing or crash. Thus, there is a need for an aircraft cargo and seating pallet having improved strength and durability.
Air cargo pallets are typically secured to the cargo bay of an aircraft with a securing mechanism located in the cargo bay. The securing mechanism is a permanent assembly or subsystem of the aircraft, while the pallets can be installed into and removed from the aircraft, as needed. The pallets are typically “notched,” or include spaced apart flanges that extend outwardly from a lower portion of the pallet core. The securing mechanism engages these flanges and secures the pallet to the cargo bay.
While only two opposite sides of the pallet are generally secured in the cargo bay, existing air cargo pallets typically include flanges on all four sides of the pallet. As a result, the flanges, which are generally approximately two inches in length, protrude from the pallet on all sides. Air cargo pallets are generally positioned in a cargo bay with the flanges on one pallet located very close to the flanges on neighboring pallets, to maximize the available space in the cargo bay.
This pallet spacing configuration often leads to problems, as passengers may drop items between neighboring pallets and have a difficult time retrieving the items, due to the small opening (approximately four inches) between the pallets and the flanges located in the opening. Moreover, passengers may inadvertently step into the opening, causing them to fall or be injured.